In recent years, a hybrid vehicle draws public attention as an eco-friendly vehicle. The hybrid vehicle is a vehicle provided with a power storage device, an inverter and an electric motor driven by the inverter as a power source for vehicle traveling in addition to a conventional internal combustion engine.
With regard to such a hybrid vehicle, there is a known hybrid vehicle capable of traveling by switching between a first traveling mode for traveling while stopping the internal combustion engine and a second traveling mode for traveling while operating the internal combustion engine in accordance with a vehicle state.
For example, Japanese Patent Laying-open No. 2005-146910 discloses a hybrid vehicle in which switching from a first traveling mode to a second traveling mode is prohibited until warming of a catalyst for purifying exhaust gas of an engine is completed and switching to the second traveling mode is permitted after the catalyst is heated up to a predetermined temperature.
However, in the hybrid vehicle disclosed in Japanese Patent Laying-open No. 2005-146910, the traveling mode is switched without consideration to a temperature of a fuel supplying system. Therefore, as described below, corrosion of a fuel pipe, that is, dry corrosion may be generated.
The dry corrosion is a phenomenon where aluminum is corroded by alcohol containing fuel. Particularly, under the environment of a high temperature and a low water concentration, oxidation corrosion of aluminum is radically developed. In a case where at least a part of the fuel pipe is made of aluminum, and when a traveling time in the first traveling mode is long, it is not possible to obtain a cooling effect of the fuel pipe by fuel supplied from a fuel tank to the fuel pipe. Therefore, due to influences such as solar radiation and an atmosphere around the engine, the temperature of the fuel pipe is increased so as to generate the dry corrosion.
Particularly, in a plug-in hybrid vehicle capable of charging the power storage device from a power source outside the vehicle (system power supply), a traveling distance with only electric power stored from the power source outside the vehicle into the power storage device is extended and the traveling time in the first traveling mode for traveling while stopping the internal combustion engine is long. Therefore, suppressing the generation of the dry corrosion is an important problem.